In the prior art, forecast of future trend in changes of certain information is generally based on historical data of the information. However, because the information change is usually affected by other factors, for example, the search volume of keywords can be affected by factors such as the delivery area of the keywords and the time, or as another example, the link click counts may be correlated with factors such as the search volume of the keywords contained in the links and the presentation area of the link, the future trend in the changes of the information cannot be properly pre-estimated based on the historical data of the information only. Particularly, when a user frequently adjusts some factors, for example, the user adjusts the desired advertising area and time, etc. of the keywords, forecasting and estimating of the future trend in the change of the relevant information becomes more difficult.